hot water stop cock

[John.Stitch]

My parents have an interesting plumbing system.
They have a new washing machine arrivng tommorrow. I undid the hot water plastic pipe supply to the existing WM. The stop cock on the end of the HW pipe did not stop the water completely, so I have a leak.

So If I cannot turn it off can I find the stop cock for the HW?

Err not sure which it is.

The gravity fed system is as follows.
Aga acts as the boiler to heat the hot water and to supply a rad in the bathroom.

Hot water cylinder has no stop cock for the hot water from the pipe coming from the top of the cylinder. Not sure if it should. cannot find another in the pipe.

Emersion heater in water cylinder

There are stop cocks on pipes.
One on the pipe at the back of the cyl that takes water upto overflow in one of the two reservoirs in the attic, and one on the pipe that supplies cold water from the other attic reservoir to the pipe that comes off the front bottom of the cylinder, one with the drain cock on it

So is the only way to turn off the cold supply to the cylinder and to drain the cylinder or is there another way?

 

[chrishutt]

one on the pipe that supplies cold water from the other attic reservoir to the pipe that comes off the front bottom of the cylinder, one with the drain cock on it

That's the one you shut to stop the hot water flow.